Functionalization of carbon nanotubes by water plasma

Abstract

Multiwall carbon nanotubes grown by plasma enhanced chemical vapour deposition were functionalized by H(2)O plasma treatment. Through a controlled functionalization process of the carbon nanotubes (CNTs) we were able to modify and tune their chemical reactivity, expanding the range of potential applications in the field of energy and environment. In particular, different oxygen groups were attached to the surfaces of the nanotubes (e.g. carboxyl, hydroxyl and carbonyl), which changed their physicochemical properties. In order to optimize the main operational parameters of the H(2)O plasma treatment, pressure and power, a Box-Wilson experimental design was adopted. Analysis of the morphology, electrochemical properties and functional groups attached to the surfaces of the CNTs allowed us to determine which treatment conditions were suitable for different applications. After water plasma treatment the specific capacitance of the nanotubes increased from 23 up to 68 F g(-1) at a scan rate of 10 mV s(-1).

Growth and functionalization of carbon nanotubes on quartz filter for environmental applications

“…The CNTs were treated with10 W rf power and 135 Pa water pressure for 120 s, which is only specific to the removal of amorphous carbon and the introduction of different oxygen containing functional groups, without destroying the nanotubes [28].…”

“…Furthermore, it is rather difficult to control and very harsh for the graphitic walls of CNTs [25][26][27]. Our previous studies show that the CNTs surface can be cleaned and crafted with different functional groups by controlling the conditions of a plasma treatment (rf plasma power, gas composition and pressure) [28,29].…”

“…In the present work, vertically-aligned multiwall carbon nanotubes (VA-MWCNTs) were grown on quartz filters by plasma-enhanced chemical vapor deposition (PECVD). A water plasma treatment was performed on the as grown CNTs to remove the amorphous carbon, increase the defect sites and to preferentially introduce different kinds of oxygen functional groups [28]. Introduction of oxygen groups on the surface of CNTs through a water plasma treatment makes them more hydrophilic and allows us to increase the interactions with VOCs.…”

Surface-enhanced Raman spectroscopy characterisation of functionalised multi-walled carbon nanotubes

“…In fact, it is expected that the I D /I G ratio increases after functionalisation, because the interaction between carbon nanotube wall and functional groups produces a higher density of sp 3 hybridised carbon sites. [21][22][23][24][25][26][27][28] However, the functionalisation of MWNTs does not result in obvious changes in the I D /I G ratio and Raman spectrum in general. In fact, when a set of spectra is recorded from the same pristine MWNT sample, significant changes in the I D /I G ratio are observed, and these changes are sometimes apparently of the same order as those recorded after the chemical functionalisation.…”

Dispersion of multi-walled carbon nanotube in tetrahydrofuran functionalized with Ar/O2, Ar/N2, and Ar/N2/H2 plasma

“…Plasma discharge can also create functional groups on the surface of CNTs [7]. This is because the abundance of energetic species created in the plasma discharge gives a lot of opportunities for the functionalization [8,9].…”